Field of the Invention
The present invention relates to a novel process for producing tetrahydropyran-3-one derivatives of the formula: ##STR3## wherein R is a hydrogen atom; a straight chained or branched C.sub.1 -C.sub.10 alkyl group which is unsubstituted or substituted by a halogen atom, a hydroxyl group, a C.sub.1 -C.sub.6 alkoxy group, a C.sub.1 -C.sub.6 alkythio group, a C.sub.1 -C.sub.6 alkylcarbonyloxy group, a C.sub.1 -C.sub.6 alkoxycarbonyl group, a C.sub.1 -C.sub.6 mono- or dialkylamino group, a C.sub.3 -C.sub.6 cycloalkyl group, a C.sub.1 -C.sub.6 alkylaminocarbonyl group, a C.sub.1 -C.sub.6 alkylcarbonylamino group, a C.sub.1 -C.sub.6 alkylcarbonyl group or a phenyl or benzoyl group which is unsubstituted or substituted by a halogen atom, a C.sub.1 -C.sub.6 alkyl group, a C.sub.1 -C.sub.6 alkoxy group, a C.sub.1 -C.sub.6 akylthio group or a C.sub.1 -C.sub.6 alkoxycarbonyl group; a C.sub.3 -C.sub.6 cycloalkyl group; or a phenyl or biphenyl group which is unsubstituted or substituted by a halogen atom, a C.sub.1 -C.sub.6 alkoxy group or C.sub.1 -C.sub.6 alkylthio group.